Carburetor



Aug. 7, 1951 G. M. BICKNELL CARBURETOR Filed Jan. 28, 1946 FIG.3.

FIG.2..

INVENTOR. GEORGE M. BICKNELL ATTORNEY Patented Aug. 7, 1951 CARBURETORGeorge M. Bicknell, St. Louis, Mo., assignor to Carter CarburetorCorporation, St. Louis, Mo., a corporation of Delaware ApplicationJanuary 28, 1946, Serial No. 643,874

1 Claim.

This invention relates to carburetors for internal combustion enginesand consists particularly in means for supplying an additionalaccelerating charge to the engine under conditions when the normal fuelsupply is inadequate.

One difficulty with the usual type of accelerating pump is that thedischarge anterior to the throttle is obstructed in its passage to theengine cylinders by the throttle valve. Heretofore, in the usual type ofcarburetor in which the main fuel nozzle is anterior to the throttle, ithas not been feasible to discharge the pump posterior to the throttlebecause the high manifold suction would tend to draw fuel continuouslyfrom the pump. The inter-position of an adequate check valve in the pumpoutlet system, however, would delay and reduce the pump discharge in anundesirable manner.

It is an object of the present invention to provide a novel acceleratingpump which discharges, at least in part, posterior to the throttlevalve, but without the disadvantages above mentioned.

Another object is to provide an accelerating pump which dischargesadequately and promptly through one or both of the main and idling fuelfeeding passages.

These objects and other more detailed objects hereafter appearing areattained by the structure illustrated which:

Fig. l is a side view, partly sectioned, illustrating an internalcombustion engine carburetor embodying the invention.

Fig. 2 is a vertical section of the carburetor taken on the center lineof the mixture conduit.

Fig. 3 is a detail section taken on the line 3-3 of Fig. 1.

Fig. 4 is a similar section taken on the line 44 of Fig. l.

The automotive carburetor shown comprises a downdraft mixture conduit orbarrel 6 enclosing a series of Venturi tubes 1. The entry of air to theupper end of the conduit is controlled by a choke valve 8 and thedischarge of mixture from the lower end is controlled by a throttlevalve 9 operated in the usual manner from the drivers compartment. Afuel bowl lil mounted adjacent the mixture conduit encloses a float lland the usual needle valve mechanism (not shown) for maintaining fueltherein at a substantially constant level.

Located in the lower portion of bowl is a chamber I2 having a cover It.This chamber is connected to the bowl through a pair or restricted inthe accompanying drawing in ports l4 and [5, the larger orifice I4 beingcontrolled by a check valve [6 of the flapper type. The main nozzle lldischarges into the smallest Venturi tube 1 anterior to throttle valve9. This nozzle is connected to chamber [2 through a calibrated meteringorifice element [8 controlled by a metering pin l9 and of less effectivecapacity than orifices l4 and 15. Fuel for idling is supplied through atube 20, passages 2| and 22, and ports 23 located adjacent and posteriorto the edge of throttle valve 9 when closed. Both idling tube 20 andmain nozzle ll communicate with a well 24 which is connected throughorifice element I8 to chamber l2, this being understood as aninter-connected form of fuel system.

A circular ridge 25 formed on the outside of the fuel bowl wall adjacentchamber i2 is closed on its outer portion by a diaphragm 26 to form anaccelerating pump pressure chamber 21 which communicates through passage28 with chamber 12. The diaphragm is secured in position by a cap 29 andis constantly urged toward the right or discharging direction by acoiled spring 30 compressed between the diaphragm and cap. A plunger 3|extends right-wardly from the diaphragm through passage 28 and has acentral longitudinal orifice 32 which receives metering pin l9, thelatter being attached to the plunger by a pin 33 so that the meteringpin moves with the diaphragm. The space 34 between the diaphragm and cap29 is connected to the carburetor mixture conduit posterior to throttle9 by a suction passage 35 so that fluctuation of the diaphragm andmetering pin follow variations of suction in the engine intake conduitto which the carburetor is attached. In operation, when the carburetoris operating with the throttle closed or nearly closed and relativelyhigh suction exists in the mixture conduit posterior to the throttle,diaphragm 26 is moved to the left so as to draw a charge of fuel intopressure chamber 2'1 through orifice I l and past check valve [6.Chamber I2 is maintained full by the head of fuel in the bowl. When thesuction drops, as occurs, for instance, upon opening movement of thethrottle valve, diaphragm 26 is urged to the right by spring 38 so as toforce fuel from chamber 21 into chamber !2 and thence through themetering orifice and main nozzle i7 and the idling passages into themixture conduit. When the pressure in chamber i2 is thus increased,check valve It prevents its dissipation back into the bowl so that aprompt and adequate accelerating discharge is provided. During idlingand part throttle operation, the idling passages, normally,

3 will be full of fuel so that a substantial part of the pump discharge,upon such opening of the throttle, flows through the idling ports andreaches the engine without obstruction by the throttle plate.

This arrangement has a further advantage that during opening of thethrottle, when the discharge of fuel transfers from the idling passageto the main nozzle, the level of fuel in the main nozzle is raised so asto expedite the normal aspiration of fuel therefrom. Check valve l6 maybe omitted, if desired, as the body of fuel in chamber [2 will insure anadequate pump discharge through the various fuel passages,

The invention may be modified in this and other respects that will occurto those skilled in the art without departing from the spirit of theinvention and the exclusive use of all modifications that come withinthe scope of the appended claim is contemplated.

I claim:

In a carburetor, a mixture conduit, a liquid fuel reservoir, a main fuelsupply passage connecting said reservoir and said conduit, a normallyopen main metering orifice in said passage, an accelerating pumpcomprising a movable wall mounted adjacent the reservoir end of saidpassage and a Number GEORGE M. BICKNELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date 1,923,473 Beard Aug. 22, 1933 2,103,629Moore Dec. 28, 1937 2,182,580 Bracke Dec. 5, 1939 2,207,456 Coffey July9, 1940 2,389,922 Mennesson Nov. 27, 1945 2,407,535 Carlson et a1 Sept.10, 1946 FOREIGN PATENTS Number Country Date 521,230 Great Britain May15, 1940

